I’d start by blocking the sun before it ever hits the seat. In a small urban space, that usually means a cantilever umbrella, a shade sail stretched between walls, a slatted pergola, or tall planters with climbing vines. If the furniture is movable, shift it so the hottest afternoon sun falls on the table or walkway instead of the seating. Even a light canvas cover or reflective sunshade thrown over benches when they’re not in use makes a surprising difference.
Material matters, too. Dark metal and dark plastic bake in direct sun, so I’d choose light-colored, breathable designs: sling chairs, open-weave wicker or resin wicker, teak or bamboo, and powder-coated aluminum in a pale finish rather than black. For cushions, go for light-colored, fast-drying, breathable fabrics, and take them inside or store them in a shaded box when not in use. A simple bamboo mat or breathable seat pad can also stop the surface from feeling so hot against your skin.
For active cooling, a battery-powered misting fan or a small oscillating fan near the seating area works well on a balcony or rooftop. I’d also keep a spray bottle of water handy for a quick cool-down, but avoid soaking electrical equipment or cushions. If the seat is already hot, lay a damp light-colored towel over it for a few minutes, then wipe it dry before sitting. Finally, place furniture over lighter pavers or an outdoor rug rather than dark asphalt or stone that radiates heat, and add shade-tolerant greenery around the edges. The goal is not just cooler furniture, but a cooler little pocket of air around it.